The correct option is C PR2+QR2=PQ2
Given: △PQR, PS=QS=RS
Now, In △PRS,
PS=RS
thus, ∠SPR=∠SRP=x ...(Isosceles triangle property)
Now, In △SQR,
SQ=QR
∠SQR=∠SRQ=y ...(Isosceles triangle property)
Sum of angles of PQR = 180
∠PQR+∠PRQ+∠QPR=180
∠PQR+∠QPR+∠QRS+∠PRS=180
x+y+x+y=180
x+y=90
∠PRS+∠QRS=90
∠PRQ=90∘
Thus, △PQR, is a right angled triangle at ∠R
Thus, PR2+QR2=PQ2 ...(Pythagoras Theorem)